Gearing for elevators



(No 4Model.) 2 Sheets-Sheet l. E. B. PARKHURST.

GEARING FOR ELEVATORS.

N0. 571,864` Patented NOVn 24, 1896.

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E. B. PARKHURST. GBARING POR BLBVATURS.

Patented Nov. 24, 1896;

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EDlVARl) B. PARKiflUR-ST, OF NVOBURN, l\IASSAClUSET"S.

(BEARING FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 571,864, dated November24, 1896. Application filed November 18, 1895. Serial No. 569,274. @inmodela To all whom it' may concern:

Be it known that I, EDWARD B. ilannr-iunsr, citizen of the UnitedStates, residing at lVobnrn, in the county of Middlesex and State oflllassachusetts,have invented certain new and useful Improvements inGearing for Elevators, of which the following is a speciiication,reference being had therein to the accompanying drawings.

The invention relates more particularly to elevators of the generalclass in which the car or platform is operated by means of gears mountedon the said car or platform engaging with fixed or stationary racks andoperated hy rotating Wo1nis,\vlx.ich also are carried hy the car orplatform.

The object of the invent-ion is to simplify the gearing intermediate theWorms and the racks and to reduce the number of parts to the greatestpossible extent.

The invention will first 'he described withv reference to theaccompanying drawings, af-

ter which its distinguishing features will he more particularly pointedout and distinctly defined in the claims at the close of thisspecification.

In the accompanying drawings, Figure l, Sheet 1, is a view mainly inside elevation, but with some of the parts in vertical section, of anelevator having my invention applied thereto. Fig. 2, Sheet 2, a view inelevation, partly in section, of certain details thereof. Fig. 3 is avieny of the worm and gear which are represented inv Fig. 2, viewingthem from the left in the latter figure.

Fig. a is a view in elevation of portions ofv one of the racks and itssupport,

The preferred application of my invention is in connection with anelectric elevator, and I have shown it thus applied in Fig. 1 of thedrawings.

At lin the drawings is a car or platform of an elevator. l have hereinshown a car or platform like that in common use for freightelevat-ors,although it is to he understood that the invention is applicable toelevator-cars of other descriptions as Well.

:2 f3 are fixed or stationary uprights between which the car or platform1 moves. As will be obvious, a Well may be employed instead. of thesenprights, or the uprights may loe einployed in a Well, and so far asthis part of the construction is concerned there need be no departurefrom what is in common usc. On the uprights 2 2 are secured racks 3 3.

l is a framerat the under side of the car or platform and connectedtherewith. This frame serves for the support of the operating mechanismfor the car or platform.

5 5 are gears the teeth of which engage with the teeth of the racks 3 3,said gears being mounted on the car or platform and heing rotated bydevices mounted on and can ried by the said car or platform, asl nowwillproceed to describe.

At 6 6 are Worms engaging with the gears 5 5 for the purpose of turningthe same, and 7 is a shaft on which the said Worms G G are Iixed.Preferably the shaft 7 has fixed thereon the armature S of anelectromagnet D, "whereby it is rotated in the desired direction on thepassage of an electric current through the Wi ring of the said magnet.

Each gear 5 5 meshes directly with the adjacent rack E3 and also withthe adjacent Worm U, and thus serves both as a spnrpinion and as aworm-gear. illeretofore it has been found necessary to employ more thanone gear intermediate cach Worm and the adjacent rack, inasmuch as asingle gear of ordinary construction is not fitted to serve both as aWorm gear to coact with the Worm and as a spur gear orpinion to eoactwith the rack. It is found necessary in practice, in the case of awormgcar, to form the surfaces of the teeth thereof on an inclinerelative to `the axis on which the Worm-gear rotates corresponding withthe inclination of the thread of the Worm. Spur gears and pinions havethe intermeshing surfaces of the teeth thereof formed parallel with theaxes on which the said gears rotate. In accordance with my presentinvention I form one side 51 of every tooth of each gear 5 inclined tocorrespond with the thread of the Worm 6, and I form the oppositesurface 52 of over f tooth of such gear 5 parallel with the axis of thegear 5, to thereby nt it to Work against the teeth of the rack 3. Thesefeatures are most clearly shown in Fi gs. 2 and 3. In other Words, Iforni every tooth of each gear 5 with one surface thereof in-V clinedrelatively to the axis of rotation of the said gear to correspond Withthe inclination of the thread of the adjacent Worm G, and I ICO form theother surface of every tooth of said gear parallel with the aXis ofrotation of the gear. As will be understood, the teeth 3l of each rack 3have horizontal Working' surfaces 32, with which the surfaces 52 of theteeth of the corresponding Worm-gear 5 engage. The tapering formpossessed by the teeth of each gear 5 enables me to forni the teeth 3lof each rack 3 tapering also, which I do for the purpose ofstrengthening the said teeth 3l by the introduction of more metal intothe saine in the broader portions thereof. I secure further strength byconnecting the ends of the teeth on each rack by means of Webs 33,extendinglongitudinally of the rack at each side thereof.

I claim as my invcntionl. The combination with vertical racks, as 3, 3,of an elevator' car or platform, gears mounted on said car or platformand provided with teeth each having' one surface thereof inclinedrelatively to the axis of the gear, as in the ease of a Worrn-gear, andthe other surface thereof parallel with said axis to engage with theteeth of the adjacent rack, Worms in engagement With the inclinedsurfaces of the teeth of the said gears, and means to rotate the saidWorms, substantially as described.

2. The gear herein described having each tooth thereof provided With onesurface which is inclined relatively to the axis of the gear, as in thecase of a Worin-gear, and the other surface thereof parallel with thesaid axis, as in the ease of a spurfgear, substantially as set forth.

In testimony whereof I affix my signature in presence of tWo Witnesses.

EDWARD B. PARKIIURST.

lVitnesses:

WM. A. MAcLnoD, CHAs. F. RANDALL.

